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sys/netinet6/frag6.c
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1 /* $NetBSD: frag6.c,v 1.26 2003/09/06 03:36:32 itojun Exp $ */ 2 /* $KAME: frag6.c,v 1.40 2002/05/27 21:40:31 itojun Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: frag6.c,v 1.26 2003/09/06 03:36:32 itojun Exp $"); 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/malloc.h> 39 #include <sys/mbuf.h> 40 #include <sys/domain.h> 41 #include <sys/protosw.h> 42 #include <sys/socket.h> 43 #include <sys/errno.h> 44 #include <sys/time.h> 45 #include <sys/kernel.h> 46 #include <sys/syslog.h> 47 48 #include <net/if.h> 49 #include <net/route.h> 50 51 #include <netinet/in.h> 52 #include <netinet/in_var.h> 53 #include <netinet/ip6.h> 54 #include <netinet6/in6_pcb.h> 55 #include <netinet6/ip6_var.h> 56 #include <netinet/icmp6.h> 57 58 #include <net/net_osdep.h> 59 60 /* 61 * Define it to get a correct behavior on per-interface statistics. 62 * You will need to perform an extra routing table lookup, per fragment, 63 * to do it. This may, or may not be, a performance hit. 64 */ 65 #define IN6_IFSTAT_STRICT 66 67 static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *)); 68 static void frag6_deq __P((struct ip6asfrag *)); 69 static void frag6_insque __P((struct ip6q *, struct ip6q *)); 70 static void frag6_remque __P((struct ip6q *)); 71 static void frag6_freef __P((struct ip6q *)); 72 73 static int ip6q_locked; 74 u_int frag6_nfragpackets; 75 u_int frag6_nfrags; 76 struct ip6q ip6q; /* ip6 reassemble queue */ 77 78 static __inline int ip6q_lock_try __P((void)); 79 static __inline void ip6q_unlock __P((void)); 80 81 static __inline int 82 ip6q_lock_try() 83 { 84 int s; 85 86 /* 87 * Use splvm() -- we're bloking things that would cause 88 * mbuf allocation. 89 */ 90 s = splvm(); 91 if (ip6q_locked) { 92 splx(s); 93 return (0); 94 } 95 ip6q_locked = 1; 96 splx(s); 97 return (1); 98 } 99 100 static __inline void 101 ip6q_unlock() 102 { 103 int s; 104 105 s = splvm(); 106 ip6q_locked = 0; 107 splx(s); 108 } 109 110 #ifdef DIAGNOSTIC 111 #define IP6Q_LOCK() \ 112 do { \ 113 if (ip6q_lock_try() == 0) { \ 114 printf("%s:%d: ip6q already locked\n", __FILE__, __LINE__); \ 115 panic("ip6q_lock"); \ 116 } \ 117 } while (/*CONSTCOND*/ 0) 118 #define IP6Q_LOCK_CHECK() \ 119 do { \ 120 if (ip6q_locked == 0) { \ 121 printf("%s:%d: ip6q lock not held\n", __FILE__, __LINE__); \ 122 panic("ip6q lock check"); \ 123 } \ 124 } while (/*CONSTCOND*/ 0) 125 #else 126 #define IP6Q_LOCK() (void) ip6q_lock_try() 127 #define IP6Q_LOCK_CHECK() /* nothing */ 128 #endif 129 130 #define IP6Q_UNLOCK() ip6q_unlock() 131 132 #ifndef offsetof /* XXX */ 133 #define offsetof(type, member) ((size_t)(&((type *)0)->member)) 134 #endif 135 136 /* 137 * Initialise reassembly queue and fragment identifier. 138 */ 139 void 140 frag6_init() 141 { 142 143 ip6q.ip6q_next = ip6q.ip6q_prev = &ip6q; 144 } 145 146 /* 147 * In RFC2460, fragment and reassembly rule do not agree with each other, 148 * in terms of next header field handling in fragment header. 149 * While the sender will use the same value for all of the fragmented packets, 150 * receiver is suggested not to check the consistency. 151 * 152 * fragment rule (p20): 153 * (2) A Fragment header containing: 154 * The Next Header value that identifies the first header of 155 * the Fragmentable Part of the original packet. 156 * -> next header field is same for all fragments 157 * 158 * reassembly rule (p21): 159 * The Next Header field of the last header of the Unfragmentable 160 * Part is obtained from the Next Header field of the first 161 * fragment's Fragment header. 162 * -> should grab it from the first fragment only 163 * 164 * The following note also contradicts with fragment rule - noone is going to 165 * send different fragment with different next header field. 166 * 167 * additional note (p22): 168 * The Next Header values in the Fragment headers of different 169 * fragments of the same original packet may differ. Only the value 170 * from the Offset zero fragment packet is used for reassembly. 171 * -> should grab it from the first fragment only 172 * 173 * There is no explicit reason given in the RFC. Historical reason maybe? 174 */ 175 /* 176 * Fragment input 177 */ 178 int 179 frag6_input(mp, offp, proto) 180 struct mbuf **mp; 181 int *offp, proto; 182 { 183 struct mbuf *m = *mp, *t; 184 struct ip6_hdr *ip6; 185 struct ip6_frag *ip6f; 186 struct ip6q *q6; 187 struct ip6asfrag *af6, *ip6af, *af6dwn; 188 int offset = *offp, nxt, i, next; 189 int first_frag = 0; 190 int fragoff, frgpartlen; /* must be larger than u_int16_t */ 191 struct ifnet *dstifp; 192 #ifdef IN6_IFSTAT_STRICT 193 static struct route_in6 ro; 194 struct sockaddr_in6 *dst; 195 #endif 196 197 ip6 = mtod(m, struct ip6_hdr *); 198 IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f)); 199 if (ip6f == NULL) 200 return IPPROTO_DONE; 201 202 dstifp = NULL; 203 #ifdef IN6_IFSTAT_STRICT 204 /* find the destination interface of the packet. */ 205 dst = (struct sockaddr_in6 *)&ro.ro_dst; 206 if (ro.ro_rt 207 && ((ro.ro_rt->rt_flags & RTF_UP) == 0 208 || !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_dst))) { 209 RTFREE(ro.ro_rt); 210 ro.ro_rt = (struct rtentry *)0; 211 } 212 if (ro.ro_rt == NULL) { 213 bzero(dst, sizeof(*dst)); 214 dst->sin6_family = AF_INET6; 215 dst->sin6_len = sizeof(struct sockaddr_in6); 216 dst->sin6_addr = ip6->ip6_dst; 217 } 218 rtalloc((struct route *)&ro); 219 if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL) 220 dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp; 221 #else 222 /* we are violating the spec, this is not the destination interface */ 223 if ((m->m_flags & M_PKTHDR) != 0) 224 dstifp = m->m_pkthdr.rcvif; 225 #endif 226 227 /* jumbo payload can't contain a fragment header */ 228 if (ip6->ip6_plen == 0) { 229 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset); 230 in6_ifstat_inc(dstifp, ifs6_reass_fail); 231 return IPPROTO_DONE; 232 } 233 234 /* 235 * check whether fragment packet's fragment length is 236 * multiple of 8 octets. 237 * sizeof(struct ip6_frag) == 8 238 * sizeof(struct ip6_hdr) = 40 239 */ 240 if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) && 241 (((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) { 242 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 243 offsetof(struct ip6_hdr, ip6_plen)); 244 in6_ifstat_inc(dstifp, ifs6_reass_fail); 245 return IPPROTO_DONE; 246 } 247 248 ip6stat.ip6s_fragments++; 249 in6_ifstat_inc(dstifp, ifs6_reass_reqd); 250 251 /* offset now points to data portion */ 252 offset += sizeof(struct ip6_frag); 253 254 IP6Q_LOCK(); 255 256 /* 257 * Enforce upper bound on number of fragments. 258 * If maxfrag is 0, never accept fragments. 259 * If maxfrag is -1, accept all fragments without limitation. 260 */ 261 if (ip6_maxfrags < 0) 262 ; 263 else if (frag6_nfrags >= (u_int)ip6_maxfrags) 264 goto dropfrag; 265 266 for (q6 = ip6q.ip6q_next; q6 != &ip6q; q6 = q6->ip6q_next) 267 if (ip6f->ip6f_ident == q6->ip6q_ident && 268 IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) && 269 IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst)) 270 break; 271 272 if (q6 == &ip6q) { 273 /* 274 * the first fragment to arrive, create a reassembly queue. 275 */ 276 first_frag = 1; 277 278 /* 279 * Enforce upper bound on number of fragmented packets 280 * for which we attempt reassembly; 281 * If maxfragpackets is 0, never accept fragments. 282 * If maxfragpackets is -1, accept all fragments without 283 * limitation. 284 */ 285 if (ip6_maxfragpackets < 0) 286 ; 287 else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets) 288 goto dropfrag; 289 frag6_nfragpackets++; 290 q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE, 291 M_DONTWAIT); 292 if (q6 == NULL) 293 goto dropfrag; 294 bzero(q6, sizeof(*q6)); 295 296 frag6_insque(q6, &ip6q); 297 298 /* ip6q_nxt will be filled afterwards, from 1st fragment */ 299 q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6; 300 #ifdef notyet 301 q6->ip6q_nxtp = (u_char *)nxtp; 302 #endif 303 q6->ip6q_ident = ip6f->ip6f_ident; 304 q6->ip6q_arrive = 0; /* Is it used anywhere? */ 305 q6->ip6q_ttl = IPV6_FRAGTTL; 306 q6->ip6q_src = ip6->ip6_src; 307 q6->ip6q_dst = ip6->ip6_dst; 308 q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */ 309 310 q6->ip6q_nfrag = 0; 311 } 312 313 /* 314 * If it's the 1st fragment, record the length of the 315 * unfragmentable part and the next header of the fragment header. 316 */ 317 fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK); 318 if (fragoff == 0) { 319 q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) - 320 sizeof(struct ip6_frag); 321 q6->ip6q_nxt = ip6f->ip6f_nxt; 322 } 323 324 /* 325 * Check that the reassembled packet would not exceed 65535 bytes 326 * in size. 327 * If it would exceed, discard the fragment and return an ICMP error. 328 */ 329 frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset; 330 if (q6->ip6q_unfrglen >= 0) { 331 /* The 1st fragment has already arrived. */ 332 if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) { 333 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 334 offset - sizeof(struct ip6_frag) + 335 offsetof(struct ip6_frag, ip6f_offlg)); 336 IP6Q_UNLOCK(); 337 return (IPPROTO_DONE); 338 } 339 } else if (fragoff + frgpartlen > IPV6_MAXPACKET) { 340 icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, 341 offset - sizeof(struct ip6_frag) + 342 offsetof(struct ip6_frag, ip6f_offlg)); 343 IP6Q_UNLOCK(); 344 return (IPPROTO_DONE); 345 } 346 /* 347 * If it's the first fragment, do the above check for each 348 * fragment already stored in the reassembly queue. 349 */ 350 if (fragoff == 0) { 351 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 352 af6 = af6dwn) { 353 af6dwn = af6->ip6af_down; 354 355 if (q6->ip6q_unfrglen + af6->ip6af_off + af6->ip6af_frglen > 356 IPV6_MAXPACKET) { 357 struct mbuf *merr = IP6_REASS_MBUF(af6); 358 struct ip6_hdr *ip6err; 359 int erroff = af6->ip6af_offset; 360 361 /* dequeue the fragment. */ 362 frag6_deq(af6); 363 free(af6, M_FTABLE); 364 365 /* adjust pointer. */ 366 ip6err = mtod(merr, struct ip6_hdr *); 367 368 /* 369 * Restore source and destination addresses 370 * in the erroneous IPv6 header. 371 */ 372 ip6err->ip6_src = q6->ip6q_src; 373 ip6err->ip6_dst = q6->ip6q_dst; 374 375 icmp6_error(merr, ICMP6_PARAM_PROB, 376 ICMP6_PARAMPROB_HEADER, 377 erroff - sizeof(struct ip6_frag) + 378 offsetof(struct ip6_frag, ip6f_offlg)); 379 } 380 } 381 } 382 383 ip6af = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE, 384 M_DONTWAIT); 385 if (ip6af == NULL) 386 goto dropfrag; 387 bzero(ip6af, sizeof(*ip6af)); 388 ip6af->ip6af_head = ip6->ip6_flow; 389 ip6af->ip6af_len = ip6->ip6_plen; 390 ip6af->ip6af_nxt = ip6->ip6_nxt; 391 ip6af->ip6af_hlim = ip6->ip6_hlim; 392 ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG; 393 ip6af->ip6af_off = fragoff; 394 ip6af->ip6af_frglen = frgpartlen; 395 ip6af->ip6af_offset = offset; 396 IP6_REASS_MBUF(ip6af) = m; 397 398 if (first_frag) { 399 af6 = (struct ip6asfrag *)q6; 400 goto insert; 401 } 402 403 /* 404 * Find a segment which begins after this one does. 405 */ 406 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 407 af6 = af6->ip6af_down) 408 if (af6->ip6af_off > ip6af->ip6af_off) 409 break; 410 411 #if 0 412 /* 413 * If there is a preceding segment, it may provide some of 414 * our data already. If so, drop the data from the incoming 415 * segment. If it provides all of our data, drop us. 416 */ 417 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 418 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 419 - ip6af->ip6af_off; 420 if (i > 0) { 421 if (i >= ip6af->ip6af_frglen) 422 goto dropfrag; 423 m_adj(IP6_REASS_MBUF(ip6af), i); 424 ip6af->ip6af_off += i; 425 ip6af->ip6af_frglen -= i; 426 } 427 } 428 429 /* 430 * While we overlap succeeding segments trim them or, 431 * if they are completely covered, dequeue them. 432 */ 433 while (af6 != (struct ip6asfrag *)q6 && 434 ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) { 435 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 436 if (i < af6->ip6af_frglen) { 437 af6->ip6af_frglen -= i; 438 af6->ip6af_off += i; 439 m_adj(IP6_REASS_MBUF(af6), i); 440 break; 441 } 442 af6 = af6->ip6af_down; 443 m_freem(IP6_REASS_MBUF(af6->ip6af_up)); 444 frag6_deq(af6->ip6af_up); 445 } 446 #else 447 /* 448 * If the incoming framgent overlaps some existing fragments in 449 * the reassembly queue, drop it, since it is dangerous to override 450 * existing fragments from a security point of view. 451 * We don't know which fragment is the bad guy - here we trust 452 * fragment that came in earlier, with no real reason. 453 */ 454 if (af6->ip6af_up != (struct ip6asfrag *)q6) { 455 i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen 456 - ip6af->ip6af_off; 457 if (i > 0) { 458 #if 0 /* suppress the noisy log */ 459 log(LOG_ERR, "%d bytes of a fragment from %s " 460 "overlaps the previous fragment\n", 461 i, ip6_sprintf(&q6->ip6q_src)); 462 #endif 463 free(ip6af, M_FTABLE); 464 goto dropfrag; 465 } 466 } 467 if (af6 != (struct ip6asfrag *)q6) { 468 i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off; 469 if (i > 0) { 470 #if 0 /* suppress the noisy log */ 471 log(LOG_ERR, "%d bytes of a fragment from %s " 472 "overlaps the succeeding fragment", 473 i, ip6_sprintf(&q6->ip6q_src)); 474 #endif 475 free(ip6af, M_FTABLE); 476 goto dropfrag; 477 } 478 } 479 #endif 480 481 insert: 482 483 /* 484 * Stick new segment in its place; 485 * check for complete reassembly. 486 * Move to front of packet queue, as we are 487 * the most recently active fragmented packet. 488 */ 489 frag6_enq(ip6af, af6->ip6af_up); 490 frag6_nfrags++; 491 q6->ip6q_nfrag++; 492 #if 0 /* xxx */ 493 if (q6 != ip6q.ip6q_next) { 494 frag6_remque(q6); 495 frag6_insque(q6, &ip6q); 496 } 497 #endif 498 next = 0; 499 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 500 af6 = af6->ip6af_down) { 501 if (af6->ip6af_off != next) { 502 IP6Q_UNLOCK(); 503 return IPPROTO_DONE; 504 } 505 next += af6->ip6af_frglen; 506 } 507 if (af6->ip6af_up->ip6af_mff) { 508 IP6Q_UNLOCK(); 509 return IPPROTO_DONE; 510 } 511 512 /* 513 * Reassembly is complete; concatenate fragments. 514 */ 515 ip6af = q6->ip6q_down; 516 t = m = IP6_REASS_MBUF(ip6af); 517 af6 = ip6af->ip6af_down; 518 frag6_deq(ip6af); 519 while (af6 != (struct ip6asfrag *)q6) { 520 af6dwn = af6->ip6af_down; 521 frag6_deq(af6); 522 while (t->m_next) 523 t = t->m_next; 524 t->m_next = IP6_REASS_MBUF(af6); 525 m_adj(t->m_next, af6->ip6af_offset); 526 free(af6, M_FTABLE); 527 af6 = af6dwn; 528 } 529 530 /* adjust offset to point where the original next header starts */ 531 offset = ip6af->ip6af_offset - sizeof(struct ip6_frag); 532 free(ip6af, M_FTABLE); 533 ip6 = mtod(m, struct ip6_hdr *); 534 ip6->ip6_plen = htons(next + offset - sizeof(struct ip6_hdr)); 535 ip6->ip6_src = q6->ip6q_src; 536 ip6->ip6_dst = q6->ip6q_dst; 537 nxt = q6->ip6q_nxt; 538 #ifdef notyet 539 *q6->ip6q_nxtp = (u_char)(nxt & 0xff); 540 #endif 541 542 /* 543 * Delete frag6 header with as a few cost as possible. 544 */ 545 if (offset < m->m_len) { 546 ovbcopy((caddr_t)ip6, (caddr_t)ip6 + sizeof(struct ip6_frag), 547 offset); 548 m->m_data += sizeof(struct ip6_frag); 549 m->m_len -= sizeof(struct ip6_frag); 550 } else { 551 /* this comes with no copy if the boundary is on cluster */ 552 if ((t = m_split(m, offset, M_DONTWAIT)) == NULL) { 553 frag6_remque(q6); 554 frag6_nfrags -= q6->ip6q_nfrag; 555 free(q6, M_FTABLE); 556 frag6_nfragpackets--; 557 goto dropfrag; 558 } 559 m_adj(t, sizeof(struct ip6_frag)); 560 m_cat(m, t); 561 } 562 563 /* 564 * Store NXT to the original. 565 */ 566 { 567 u_int8_t *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */ 568 *prvnxtp = nxt; 569 } 570 571 frag6_remque(q6); 572 frag6_nfrags -= q6->ip6q_nfrag; 573 free(q6, M_FTABLE); 574 frag6_nfragpackets--; 575 576 if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */ 577 int plen = 0; 578 for (t = m; t; t = t->m_next) 579 plen += t->m_len; 580 m->m_pkthdr.len = plen; 581 } 582 583 ip6stat.ip6s_reassembled++; 584 in6_ifstat_inc(dstifp, ifs6_reass_ok); 585 586 /* 587 * Tell launch routine the next header 588 */ 589 590 *mp = m; 591 *offp = offset; 592 593 IP6Q_UNLOCK(); 594 return nxt; 595 596 dropfrag: 597 in6_ifstat_inc(dstifp, ifs6_reass_fail); 598 ip6stat.ip6s_fragdropped++; 599 m_freem(m); 600 IP6Q_UNLOCK(); 601 return IPPROTO_DONE; 602 } 603 604 /* 605 * Free a fragment reassembly header and all 606 * associated datagrams. 607 */ 608 void 609 frag6_freef(q6) 610 struct ip6q *q6; 611 { 612 struct ip6asfrag *af6, *down6; 613 614 IP6Q_LOCK_CHECK(); 615 616 for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6; 617 af6 = down6) { 618 struct mbuf *m = IP6_REASS_MBUF(af6); 619 620 down6 = af6->ip6af_down; 621 frag6_deq(af6); 622 623 /* 624 * Return ICMP time exceeded error for the 1st fragment. 625 * Just free other fragments. 626 */ 627 if (af6->ip6af_off == 0) { 628 struct ip6_hdr *ip6; 629 630 /* adjust pointer */ 631 ip6 = mtod(m, struct ip6_hdr *); 632 633 /* restoure source and destination addresses */ 634 ip6->ip6_src = q6->ip6q_src; 635 ip6->ip6_dst = q6->ip6q_dst; 636 637 icmp6_error(m, ICMP6_TIME_EXCEEDED, 638 ICMP6_TIME_EXCEED_REASSEMBLY, 0); 639 } else 640 m_freem(m); 641 free(af6, M_FTABLE); 642 } 643 frag6_remque(q6); 644 frag6_nfrags -= q6->ip6q_nfrag; 645 free(q6, M_FTABLE); 646 frag6_nfragpackets--; 647 } 648 649 /* 650 * Put an ip fragment on a reassembly chain. 651 * Like insque, but pointers in middle of structure. 652 */ 653 void 654 frag6_enq(af6, up6) 655 struct ip6asfrag *af6, *up6; 656 { 657 658 IP6Q_LOCK_CHECK(); 659 660 af6->ip6af_up = up6; 661 af6->ip6af_down = up6->ip6af_down; 662 up6->ip6af_down->ip6af_up = af6; 663 up6->ip6af_down = af6; 664 } 665 666 /* 667 * To frag6_enq as remque is to insque. 668 */ 669 void 670 frag6_deq(af6) 671 struct ip6asfrag *af6; 672 { 673 674 IP6Q_LOCK_CHECK(); 675 676 af6->ip6af_up->ip6af_down = af6->ip6af_down; 677 af6->ip6af_down->ip6af_up = af6->ip6af_up; 678 } 679 680 void 681 frag6_insque(new, old) 682 struct ip6q *new, *old; 683 { 684 685 IP6Q_LOCK_CHECK(); 686 687 new->ip6q_prev = old; 688 new->ip6q_next = old->ip6q_next; 689 old->ip6q_next->ip6q_prev= new; 690 old->ip6q_next = new; 691 } 692 693 void 694 frag6_remque(p6) 695 struct ip6q *p6; 696 { 697 698 IP6Q_LOCK_CHECK(); 699 700 p6->ip6q_prev->ip6q_next = p6->ip6q_next; 701 p6->ip6q_next->ip6q_prev = p6->ip6q_prev; 702 } 703 704 /* 705 * IPv6 reassembling timer processing; 706 * if a timer expires on a reassembly 707 * queue, discard it. 708 */ 709 void 710 frag6_slowtimo() 711 { 712 struct ip6q *q6; 713 int s = splsoftnet(); 714 715 IP6Q_LOCK(); 716 q6 = ip6q.ip6q_next; 717 if (q6) 718 while (q6 != &ip6q) { 719 --q6->ip6q_ttl; 720 q6 = q6->ip6q_next; 721 if (q6->ip6q_prev->ip6q_ttl == 0) { 722 ip6stat.ip6s_fragtimeout++; 723 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 724 frag6_freef(q6->ip6q_prev); 725 } 726 } 727 /* 728 * If we are over the maximum number of fragments 729 * (due to the limit being lowered), drain off 730 * enough to get down to the new limit. 731 */ 732 while (frag6_nfragpackets > (u_int)ip6_maxfragpackets && 733 ip6q.ip6q_prev) { 734 ip6stat.ip6s_fragoverflow++; 735 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 736 frag6_freef(ip6q.ip6q_prev); 737 } 738 IP6Q_UNLOCK(); 739 740 #if 0 741 /* 742 * Routing changes might produce a better route than we last used; 743 * make sure we notice eventually, even if forwarding only for one 744 * destination and the cache is never replaced. 745 */ 746 if (ip6_forward_rt.ro_rt) { 747 RTFREE(ip6_forward_rt.ro_rt); 748 ip6_forward_rt.ro_rt = 0; 749 } 750 if (ipsrcchk_rt.ro_rt) { 751 RTFREE(ipsrcchk_rt.ro_rt); 752 ipsrcchk_rt.ro_rt = 0; 753 } 754 #endif 755 756 splx(s); 757 } 758 759 /* 760 * Drain off all datagram fragments. 761 */ 762 void 763 frag6_drain() 764 { 765 766 if (ip6q_lock_try() == 0) 767 return; 768 while (ip6q.ip6q_next != &ip6q) { 769 ip6stat.ip6s_fragdropped++; 770 /* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */ 771 frag6_freef(ip6q.ip6q_next); 772 } 773 IP6Q_UNLOCK(); 774 }
Cache object: 73ab4e5230b6331df0027a7f83b8769a
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